This is a two-step process:  cleaning the logos and sizing them. Two tools are helpful:

1. Cleaning the logos with PaintshopPro

Download here:

Remove as much extra space around the logos as possible.

Cut out and paste the logo into a new file with the freehand tool

Logos must be dark text on a white background to appear appropriately on the order.

For logos with inverse text, choose the Negative Image from the Colors menu:

You may still have a dark background, so you need to cut that out:

Choose the Magic Wand tool. Hold down the Shift key while tapping in the space you want to select. The Shift key allows you to select multiple spaces.

You can delete the dark background, but this may create a muddy logo or be too much trouble to work with. You might be better off searching Google for an image of logo components and creating a new logo like this: (The second logo uses the image icon from the web with simple text tools in PSP.)

Some logos do not download well from the web. For instance, the first logo below downloaded. The second was right-click copied, pasted into PaintshopPro and saved.

2. Batch re-sizing logos with Irfanview

Download this free software for Windows computers:

The aspect ratio is 1.5, so we'll save as 200 tall by 300 wide.

We'll save all logos as JPGs with the least compression ratio. (JPGs don't have the multi-layer problems that you might have with PNGs.)

From the File menu, choose Batch Conversion/Rename

Set Output format to JPG and, under Options, choose Save quality of good (100).

Then choose the Advanced button.

Set the long side to 300 pixels, which is good for almost all logos

The canvas is the area around the image; set it to 300 wide by 200 high, and choose white as the background color.

Create an Output directory for your logos that you'll remember:

Choose Add all for your input files

Choose Start Batch in the bottom left, and your files will be formatted and added to your NewLogos directory.